Heat sensitive recording material

ABSTRACT

A HEAT SENSITIVE RECORDING MATERIAL CONTAINING AT LEAST ONE OF LACTONE COMPOUNDS HAVING THE GENERAL FORMULA, (WHEREIN R2 IS SELECTED FROM THE GROUP CONSISTING OF HYDROGEN, A LOWER ALKYL GROUP OF 1 TO 5 CARBON ATOMS, A LOWER ALKOXY GROUP OF 1 TO 5 CARBON ATOMS, AMINO GROUP, A LOWER ALKYL AMINO GROUP OF 1 TO 5 CARBON ATOMS AND BENZYL AMINO GROUP; R1 AND R3 ARE SELECTED FROM THE GROUP CONSISTING OF THE SAME MEMBERS AS ABOVE DEFINED ON R2 EXCEPT THAT BENZYL AMINO GROUP IS EXCLUDED; AT LEAST ONE OF R1 AND R2 ARE SELECTED FROM AMINO GROUP, A LOWER ALKYL AMINO GROUP OF 1 TO 5 CARBON ATOMS AND BENZYL AMINO GROUP; R5 IS SELECTED FROM THE GROUP CONSISTING OF HYDROGEN, A LOWER ALKYL GROUP OF 1 TO 5 CARBON ATOMS, A LOWER ALKOXY GROUP OF 1 TO 5 CARBON ATOMS, HALOGENES, A LOWER ALKYL AMINO GROUP OF 1 TO 5 CARBON ATOMS, BENZYL AMINO GROUP AND ARYL AMINO GROUP; AND R4,R6 AND R7 ARE SELECTED FROM THE GROUP CONSISTING OF THE SAME MEMBERS AS ABOVE DEFINED ON R5 EXCEPT THAT ARYL AMINO GROUP IS EXCLUDED) AND AT LEAST ONE PHENOL COMPOUNDS.     (PHTHALAN-1,9&#39;&#39;-XANTHENE)   3-(O=),1&#39;&#39;-R4,2&#39;&#39;-R5,3&#39;&#39;-R6,4&#39;&#39;-R7,5&#39;&#39;-R1,6&#39;&#39;-R2,7&#39;&#39;-R3-SPIRO

United States Patent 3,825,432 HEAT SENSITIVE RECORDING MATERIAL Kiyoshi Futaki and Masaya Motoki, Kyoto, Japan, assignors to Mitsubishi Paper Mills, Ltd., Tokyo, Japan N Drawing. Filed Mar. 9, 1971, Ser. No. 122,521 Claims priority, application Japan, Mar. 10, 1970, 45/ 19,758 Int. Cl. C09d 11/00; C09k 3/00 US. Cl. 106-21 9 Claims ABSTRACT OF THE DISCLOSURE A heat sensitive recording material containing atleast one of lactone compounds having the general formula,

(wherein R is selected from the group consisting of hydrogen, a lower alkyl group of 1 to carbon atoms, a lower alkoxy group of 1 to 5 carbon atoms, amino group, a lower alkyl amino group of l to 5 carbon atoms and benzyl amino group; R and R are selected from the group consisting of the same members as above defined on R except that benzyl amino group is excluded; at least one of R and R are selected from amino group, a lower alkyl amino group of 1 to 5 carbon atoms and benzyl amino group; R is selected from the group consisting of hydrogen, a lower alkyl group of 1 to 5 carbon atoms, a lower alkoxy group of 1 to 5 carbon atoms, halogenes, a lower alkyl amino group of 1 to 5 carbon atoms, benzyl amino group and aryl amino group; and R R and R are selected from the group consisting of the same members as above defined on R except that aryl amino group is excluded) and at least one phenol compounds.

This invention concerns a heat sensitive composition for heat sensitive recording material and a heat sensitive recording material containing the same. More particularly, it relates to a heat sensitive recording material containing phenol compounds and usually colorless lactone compounds capable of being colored by reaction with said phenol compound when heated.

The heat sensitive recording material containing phenol compounds and lactone compounds as reaction color former is prepared by applying to a support a mixture of solutions which are obtained by separately dispersing said phenol compound and lactone compound in mediums containing binders of water or petroleum system in finely divided particle form. Also, the recording material may be produced by first impregnating either one component of said color former in a paper and thereafter applying to said paper a solution obtained by dispersing the other component in a binder. Furthermore, it may be produced 3,825,432 Patented July 23, 1974 by separately applying said two components to two separate supports and putting one upon another in such a manner that the applied coatings of the two supports contact with each other. In any case, it is necessary that the reaction color former be dispersed in binder and the like in finely divided particle form.

The color forming mechanism of this heat sensitive recording material is considered that since phenol compounds and lactone compounds are dispersed in the heat sensitive recording material produced as mentioned above, application of heat thereto causes melting or sublimation of one or both of said two components to form color. Therefore, it is required that each component of the reaction color former used in this invention is in colorless crystal form at normal temperature and it has not so low melting point to prevent formation of color during storage of the heat sensitive recording material.

In Japanese Patent Publication No. 3,680/ 69, a combination of phenols and some photochromical benzoindolinospiropyrane as a reaction color former has been proposed.

As the result of research on substances other than photochromical benzoindolinospiropyrane which may be used together with phenols to form color, the inventors have found that lactone compounds which have been used in pressure sensitive paper recently used for slip papers can be used jointly with phenols to form color with heat and a heat sensitive paper may be produced by containing the combination of the two in a support. I

The lactone compounds used in this invention have the general formula,

R1 R1 R2 I \l/\/ Re Ra I (wherein R is selected from the group consisting of hydrogen, a lower alkyl group of 1 to 5 carbon atoms, a lower alkoxy group of 1 to 5 carbon atoms, amino group, a lower alkyl amino group of 1 to 5 carbon atoms and benzyl amino group; R and R are selected from the group consisting of the same members as above defined on R; except that benzyl amino group is excluded; at least one of R and R are selected from amino group, a lower alkyl amino group of 1 to 5 carbon atoms and benzyl amino group; R is selected from the group consisting of hydrogen, a lower alkyl group of 1 to 5 carbon atoms, a lower alkoxy group of l to 5 carbon atoms, halogenes, a lower alkyl amino group of 1 to 5 carbon atoms, benzyl amino group and aryl amino group; and R R and R are selected from the group consisting of the same members as above denfied on R except that aryl amino group is excluded).

Representative of the lactone compounds shown in said general formula are shown in the following table.

Melting point Formed color Ra Ra R4 Ra Ra R1 C.) tones NH; H H CH3 CH H 256-257 Yellow. NH: H H C(CHa)a H H 203-205 Orange yellow. NH: H CHa H CH3 265-267 Yellow. NH: H H CHa H CHa 265-269 Orange. NHz H CH3 H CH: H 257-260 Yellow. NH; H H OH(CHa)z CH3 H 183-185 Orange yellow. H CH3 H CH3 H H 230-234 Light pink. H OH; H CH3 CH3 H 195-200 Greenish blue. H O CH; H CH3 CH3 H 262-263 ellow. N(C2H5)2 H H OCH: H H 160463 Light pink. N(CzH)2 H H CH3 CH3 H 210 Vermilion. N (CzHs)z H H Cl CH H 235 Red. N (CzH5)z H H N(C2Hs)z H H 172-174 Green.

14 H N(C2Hs)z H H H H 165-167 Greenish black.

N CH2 15 H N(CH3)2 H H H H 208-211 Green.

16 H H H Same as above H H 202-203 Dark green.

N CH 2 17 H N(C2H6)2 H H H H 176-178 D0.

NH- N(CH:)2

18 H N(C2Hn)2 H H H H 186-188 D0.

NH- NH 19 H N(C2H5)2 H H H H 172473 D0.

N o'rE.The formed color tones are those obtained by mixing lactone compounds and bisphenol A in a weight ratio 1:1:2 and heating and melting the mixture.

The synthesis of said lactone compounds is illustrated in the following Reference Examples.

REFERENCE EXAMPLE 1 Synthesis of lactone compound (1) COOH lactone compound REFERENCE EXAMPLE 2 Synthesis of lactone compound (10) ZHMN OH 1 t ac one C o compound (10) COOH OCH:

25.3 Grams of 4-diethylamino-2-hydroxy-2'-carboxybenzophenone and 12.4 g. of p-methoxy phenol were mixed with 250 g. of 50% sulfuric acid and the mixture was reflux heated at 122124 C. for 5 hours. Then, the mixture was poured to 1100 cc. of 10% sodium hydroxide solution with heat. Thus separated product was purified with toluene and active carbon to obtain 3.1 g. of colorless crystal of lactone compound (10).

REFERENCE EXAMPLE 3 Synthesis of lactone compound (12) (CzH5)2N' OH HO- CH3 1 t 0 ac one I com- (|3=O 01 pound (12) COOH 30 Grams of 4-diethyl amino-2-hydroxy-2'-carboxybenzophenone and 15.3 g. of 3-methyl-4-chlorophenol were mixed with 230 g. of 50% sulfuric acid and the mixture was reflux heated at 122-125 C. for 4 hours. The mixture was poured to 1100 cc. of 10% sodium hydroxide solution with heat. Thus separated product was purified with toluene and active carbon to obtain 4.6 g. of colorless crystal of lactone compound (12).

REFERENCE EXAMPLE 4 Synthesis of lactone compound (14) 2H5) zN- O H COOH CH N\ lactone compound (14) CI-I;

35 Grams of 4-diethylamino-2-hydroxy-2'-carboxybenzophenone and 18 g. of 4-dibenzy1amino-phenol were mixed with 350 g. of 50% sulfuric acid and the mixture was reflux heated at about 125 C. for 5 hours. Then, the mixture was poured to 1200 cc. of 10% sodium hydroxide solution with heat. Thus separated product was purified with toluene and active carbon to obtain 5.3 g. of light purple crystal of lactone compound (14).

REFERENCE EXAMPLE 5 47 G f 4 d h 1 2 h d 2 b rams o let y aminoy roxy- -car oxy- Synthesls of the lactone compound (19) benzophenone and 4.8 g. of p-(N-methyl-N-4-tolyl) H aminophenol were dissolved in 30 ml. of concentrated 5 sulfuric acid and the solution was stirred for 2.5 hours 0:0 at 80 C. The reaction product was thrown into ice I water and neutralized with 2N-sodiurn hydroxide. Separated product Was filtered out and dried and then extracted with benzene. The extracted product was concentrated and methanol was added thereto to separate crystals, which were then recrystallized with ethyl acetate to obtain 3.1 g. of crystal of lactone compound (19). lactone compound (19) As the phenol compound which is the other component N of the reaction color former, those containing OH group in aromatic ring are especially preferable. Representative thereof are as follows:

Phenol compounds Melting polnt Number Structural formula Rational formula C.)

A 4-tertiary butyl 94-99 (CHs)aC-OH phenol.

B 4-phenyl phenyl 166-167 C OH a-napllthol 95-96 D B-naphthol 119-122 joist E 4-hydroxy acetophe- 108-110 CHaCO- -OH none.

F OH OH 2,2-dihydroxy 103-109 I diphenyl.

G OH OH 2,2-methylene bis(4- 164 chlorophenol). Q- ()1 01 H (CH3) 0 OH OH C(CHs): 2,2-methylene biS(4- -130 I I methylfi-tertiary butyl phenol). CH2-- 1 CH3 CH3 I CH3 4,4-isopropylidene 156 diphenol.

I Cl 01 4,4-isopropylidene 90-91 (EH3 bis(24:hlorophenol). HO- OH K C1 C1 4,4-isopropylidene CH3 bis(2,6-dichloro l phenol). HO ('3- OH CH3 C1 01 L 4,4-isopropylidene 172-174 Br Br OH; HO- ({1 -OH l C 3 Br Br bis(2,6-dibromo phenol) TABLE-Continued Phenol compounds Melting point Number Structural formula Rational formula C.)

M C H; C H; 4,4-isopropylidone 136 H bis(2-mothyl I phenol). HO (l3-- 0 H N C II; (3 Hg 0 H; 4, 4-isopropylidene 168 I II bis(2, B-dimothyl phenol). H O- -O- -OH 1 l C Ha C Ha C 0 CH3 4, secondary butyl- 118-121 I idene diphenol. HO- (l3 OH P Cl OH OH 01 2,2-thlobis (4,6-di-- Paper is considered suitable as a support sheet used in this invention in view of hardness, absorbability, light and heat coeflicients, required opaqueness and transparency, cheapness and flexibility. However, if desired, synthetic resin films, woven fabric sheet, etc. may also be used.

The blending ratio of the lactone compounds and the phenol compounds is preferably 0.5- weight parts of the latter per 1 part of the former, but is not critical. However, usually, 4-8 weight parts of the phenols is used per 1 part of the lactone compounds, but the blending ratio depends upon chemical reaction and any blending ratios may cause formation of color. That is, numerical criticality of the ratio is not significant.

The phenol compounds and lactone compounds used as a reaction color former should be ground as fine as possible, specifically as fine as serveral ,u to increase resolving power of the recorded image.

As the binder which serves for binding the reaction color former, the generally known water soluble resin may be satisfactorily used and examples thereof are polyvinyl alcohol, methyl cellulose, hydroxyethyl cellulose, gum arabic, gelatin, casein, polyvinyl pyrrolidone, copolymer of styrene and maleic anhydride, polyacrylic acid salt and copolymer thereof, terpene resin, petroleum resin, cyclized rubber, etc.

Furthermore, if necessary, white pigments of strong covering power such as titanium oxide, zinc oxide, diatomaceous earth, clay, silica, talc, etc. may be incorporated to prevent stain of background and improve whiteness.

The heat sensitive recording paper of this invention as obtained in accordance with the above mentioned manner has various characteristics such as higher concentration of formed color, little color formation of background, little color formation due to friction, etc. as compared with the conventional recording paper of this kind.

This invention is illustrated with reference to Examples below.

EXAMPLE 1 Liquid (I) G. Lactone compound (1) 1 5% aqueous polyvinyl alcohol solution 50 Liquid (II) G. Phenol compound (B) 5 5% aqueous polyvinyl alcohol solution ehlorophenol).

Said liquids (I) and (II) were separately ground and dispersed with ball mill for about 15 hours and they were mixed. Thus obtained mixture which was a heat sensitive coating liquid was applied to a general raw paper of 40 g./m. in a such manner that the applied amount after drying was about 4 g./m. and the paper was dried to obtain a heat sensitive recording paper. This heat sensitive recording paper, when heated, formed yellow color and caused substantially no color formation of background and that due to friction.

EXAMPLE 2 A heat sensitive recording paper was obtained by the same process as in Example 1 except that lactone compound (8) was substituted for lactone compound (1) and phenol compound (I) was substituted for phenol compound (B). Said heat sensitive recording paper formed bluish green color and showed little color formation in background and little color formation due to friction.

EXAMPLE 3 A heat sensitive recording paper was obtained by the same procedure as in Example 1 except that lactone compound (14) was substituted for lactone compound 1) and phenol compound (L) was substituted for phenol compound (B). Application of heat to said heat sensitive recording paper caused formation of greenish black to exhibit the similar effect.

EXAMPLE 4 Liquid (I) G. Lactone compound (14) 0.8 Lactone compound (12) 0.2 5% aqueous hydroxy ethyl cellulose solution Liquid (II) G. Phenol compound '(I) 4.5 5% aqueous hydroxy ethyl cellulose solution 30 Said liquids (I) and (II) were separately ground and dispersed with ball mill for about 16 hours and then they were mixed. The mixture which was a heat sensitive coating liquid was applied to a general paper of g./m. so that the applied amount after drying was about 3 g./m. and dried to obtain a heat sensitive recording paper. Application of heat thereto formed black color and exhibited the similar effect.

9 EXAMPLE A base paper containing about 1% by weight of lactone compound (13) was produced by adding finely powdered lactone compound (13) at paper making. To this base paper, the solution in which liquid (II) of Example 4 was dispersed was applied so that the application amount after drying was about 1.5 g./m. and was dried to obtain a heat sensitive recording paper. Application of heat thereto caused formation of green color to exhibit the similar effect.

EXAMPLE 6 Said liquids (I) and (II) were separately ground and dispersed with ball mill for about 12 hours and then they were mixed. The mixture which was a heat sensitive coating liquid was applied to a general raw paper of 50 g./m. so that the application amount thereof after drying was about 3 g./m. and dried to obtain a heat sensitive recording paper. Application of heat thereto caused formation of orange yellow color to exhibit the similar effect.

EXAMPLE 8 Liquid I G. Lactone compound (3) 1 5% aqueous gum arabic solution 50 Clay Liquid( II) G. Phenol compound (M) 6 5% aqueous gum arabic solution 30 A heat sensitive recording paper was obtained in accordance with the procedure of Example 1 using said liquids (I) and (II). Application of heat thereto caused formation of yellow color to exhibit the similar effect.

EXAMPLE 9 Liquid (I) G. Lactone compound (13) 1 5% aqueous polyvinyl alcohol solution 60 Liquid (H) G. Phenol compound (D) 6 5% aqueous polyvinyl alcohol solution 40 Said liquids (I) and (II) were separately ground and dispersed with ball mill for about 15 hours. Each coating liquid was applied to a general raw paper of 40 g./m. and dried to obtain two heat sensitive recording papers. When heat was applied to these papers which were put upon another so that the applied faces contact with each other, green color was formed and the similar effect was obtained.

EXAMPLE 10 Example 1 was repeated except that the lactone compound (19) was used in place of the lactone compound (1) and the phenol compound (I) was used in place of phenol compound (B), to obtain a heat sensitive recording paper. When this recording paper was heated, dark green color was formed to obtain the similar effect.

What is claimed is:

1. A heat sensitive composition suitable for heat sensitive recording material which comprises at least one lactone compound having the general formula;

wherein R and R are selected from the group consisting of hydrogen, a lower alkyl group of 1 to 5 carbon atoms, a lower alkoxy group of 1 to 5 carbon atoms, an amino group and a lower alkyl amino group of 1 to 5 carbon atoms; R is selected from the group consisting of hydrogen, a lower alkyl group of 1 to 5 carbon atoms, a lower alkoxy group of l to 5 carbon atoms, an amino group, a lower alkyl amino group of 1 to 5 carbon atoms and a benzyl amino group; wherein at least one of R and R are selected from the group consisting of an amino group, a lower alkyl amino group of 1 to 5 carbon atoms and a benzyl amino group; R and R are selected from the group consisting of hydrogen, a lower alkyl group of 1 to 5 carbon atoms, a lower alkoxy group of 1 to 5 carbon atoms, halogen, a lower alkyl amino group of l to 5 carbon atoms and a benzyl amino group; R is selected from the group consisting of hydrogen, a lower alkyl group of 1 to 5 carbon atoms, a lower alkoxy group of l to 5 carbon atoms, halogen, a lower alkyl amino group of l to 5 carbon atoms and an arylamino group; R is selected from the group consisting of hydrogen and a lower alkyl group of 1 to 5 carbon atoms; at least one phenol compound and a binder wherein the lactone compound and the phenol compound are dispersed in finely divided form in the binder.

2. A heat sensitive composition according to Claim 1, wherein titanium oxide, zinc oxide, diatomaceous earth, clay, silica or talc is incorporated.

3. A heat sensitive recording material comprising a su port and the composition of Claim 1 applied to said support.

4. A heat sensitive composition according to Claim 1, wherein the blending ratio of lactone compound and phenol compound is 1:0.5-10 parts by weight.

5. A heat sensitive composition according to Claim 1, wherein the lactone compound has the formula,

and the phenol compound is 4,4'-isopropylidene diphenol. 6. A heat sensitive composition according to Claim 1 wherein a white pigment is incorporated.

2,2'-methylene bis (4-methyl-6-tert.-butyl phenol), 4,4'-

isopropylidene diphenol, 4,4-isopr0pylidene bis (2-chlorophenol), 4,4'-isopropylidene bis (2,6-dichloro phenol), 4,4'-isopropylidene bis (2,6-dibromo phenol), 4,4-isopropylidene bis (Z-methyl phenol), 4,4-isopropylidene bis (2,6-dimethyl phenol), 4,4'-sec. butylidene diphenol and 2,2-thiobis (4,6-dichlorophenol).

8. A heat sensitive composition according to Claim 1 wherein said binder is selected from the group consisting of polyvinyl alcohol, methylcellulose, hydroxyethylcellulose, gum arabic, gelatin, casein, polyvinyl pyrrolidone, copolymer of styrene and maleic anhydride salt of polyacrylic acid, terpene resin, petroleum resin and cyclized rubber.

9. A heat sensitive composition according to Claim 1 wherein R is hydrogen or amino, R is hydrogen, amino, lower alkyl amino having 1 to 2 carbon atoms in the alkyl group or benzylamino, R is hydrogen, methyl or methoxy, R is hydrogen or methyl, R is hydrogen, lower alkyl of 1 to 4 carbon atoms, methoxy, chlorine, lower alkyl amino of 2 carbon atoms, benzylamino, phenylamino, methylphenylamino, phenylaminophenylamino or tolyl methyl amino, R is hydrogen or methyl and R is hydrogen or methyl.

References Cited UNITED STATES PATENTS 3,244,550 4/1966 Farnham et al. 11736.8 3,451,338 6/1969 Baum 11736.8 3,539,375 11/1970 Baum 11736.8 3,624,107 11/1971 Lin 117--36.8 3,560,229 2/1971 Farnham et a1. 10621 ALLAN LIEBERMAN, Primary Examiner US. Cl. X. R.

106-137, 148, 193 D, 209, 241; 260-41 D, 41.5 R, 764 

